What is gscour?

gscour is a tool that helps you find all the hostnames associated with a given domain. If a company owns "example.com," this tool tries to discover related addresses like "mail.example.com," "dev.example.com," or "internal.example.com." This process is often called subdomain discovery. The project's description mentions that it's helpful during "VA/PT work," which stands for Vulnerability Assessment and Penetration Testing. In plain terms, security professionals use this tool to map out a target's online presence before trying to find security weaknesses. You need to know what assets exist before you can test if they are secure. Beyond that core purpose, the README doesn't go into detail about how the tool works under the hood or what specific techniques it uses to find these hostnames. There are no instructions on installation or usage provided in the repository documentation. This tool would be used by security researchers, penetration testers, or IT administrators who need a complete picture of an organization's internet-facing infrastructure. For example, if you are hired to test a company's security, you would run this tool first to see all the different web addresses and servers the company has, ensuring you don't miss any vulnerable entry points during your assessment.